The GOTD download is obviously a downloader at <2MB -- in my Win7 32-bit VM the installed app takes up ~46MB, with folders added to ProgramData & C:\Users\ [UserName]\ AppData\ Roaming\. The Registry gets an uninstall key, one for Apowersoft, plus a couple of entries opening up Windows firewall to let the app communicate with Apowersoft servers. Images are uploaded to have whatever work done -- a dealbreaker for folks like me on cable broadband with [very] low upload bandwidth. Putting the summary first, as a giveaway it might be cool to play with, providing you don't have or mind any upload issues, but it's most likely more a toy than serious tool. Don't get overly impressed about the AI part -- the Chinese gov is pushing AI development Super Hard, so we're probably going to see more & more apps with AI somehow part of the picture. Some will be worthwhile, some not so much.
Apps like this are a subset of the tools you'd use to copy parts of an image & paste them on top of another image. I guess marketing folks figure they'll sell more of the software by calling it a background eraser, figuring potential buyers won't notice that's it's only part of what's by necessity a more complicated solution. That's because the part you paste into or onto an image should match when it comes to size, lighting, perspective, coloring etc. AI [artificial Intelligence] can make that part easier using Deepfake tech -- wikipedia[.]org/wiki/Deepfake .
Compositing [ wikipedia[.]org/wiki/Compositing ], which is what this copying/pasting is called, starts with the selection of what you want to copy, and that can be the hardest part. Pros shoot the photos & videos they intend to use for a composite against a plain, solid color background, e.g. greenscreen, making selecting their subjects much simpler / easier -- this is widely used by individuals for the background when video conferencing, with software automatically replacing that color with the background of their choice. For product shots, e.g. seller listings on eBay, there's a huge selection of folding light boxes available cheap -- solid color [often white] translucent [to allow lighting] cubes with one side open where the object is placed inside.
Where it gets most difficult is when the object [e.g. person] you want to copy is in a photo with a more complicated background. AI can help, but so far at least, Only Help -- Adobe, with 3rd quarter 2021 revenue of $3.94 billion, has spent a Ton on AI, but it still cannot get you a perfect selection in Photoshop... it's still necessary to perform fine tuning touchup. I don't imagine smaller companies with fewer resources can somehow [magically] do better. The exact tools you'll use depend on the photo editing software you're using, but often involve tracing close to the object, with the software then trying to detect nearby object edges. You then nudge the selection, e.g. re-tracing closer to or further from the object where needed, sometimes shrinking the entire selection by one or a few pixels, often adding/applying feathering, which is a gradual tapering off of the selected object's colors, so that it will blend better with the background when pasted. Having a sharper image helps, a LOT, because those edges will be better defined. Then once you've got a good selection you can paste it in another photo/image, & while it's still a selection, adjust its size, lighting / shadows, colors etc. to make it a good fit or match.